Inter-switch link identification and monitoring

ABSTRACT

Techniques for inter-switch link (ISL) identification and monitoring are described herein. An aspect includes sending a query fabric path command to a switch, the query fabric path command including an origin address and a destination address. Another aspect includes receiving a query fabric path response from the switch based on the query fabric path command, the query fabric path response including a plurality of port identifiers. Another aspect includes monitoring a plurality of ports, each of the plurality of ports corresponding to a respective port identifier of the plurality of port identifiers in the query fabric path response.

BACKGROUND

The present invention generally relates to computer networks, and morespecifically to inter-switch link (ISL) identification and monitoring ina computer network.

Fibre channel (FC) switches are used to connect servers to storageservices and resources for creating a storage area network (SAN). Incomputing, a SAN may be a network designed to attach computer storagedevices, such as disk array controllers and tape libraries, to servers.The SAN fabric is an active intelligent interconnection scheme thatutilizes the Fibre Channel Architecture. Servers and storage devicesconnect to FC SAN switches as an N_Port (node port), while the switchprovides an F_Port (fabric port). When two or more FC SAN switches areconnected together to enlarge the switch fabric, they may utilize anE_Port (expansion port) on each end. E_Ports implement a mechanism toexchange configuration and topology information between the switches.

When the E_Ports of two switches support the same configuration andprotocol parameters, the E_Ports may establish an inter-switch link(ISL) between the two switches. The industry standard for ISLs isdefined in the T11 FC-SW-2 (and later versions) standard. ISLsestablished through E_Ports, as described above, have additionalproperties related to maintaining a consistent view of the fabric andthe various devices among all the interconnected SAN switches. Anydevice with an E_Port connection to the SAN is a peer with all theswitches, which are collectively managing and controlling the SANitself. An alteration of an E_Port link may disrupt the SAN fabricmanagement structure, and consequently may cause a momentary disruptionacross the entire SAN, while the interconnected switches re-establishthe management hierarchy and restore the switch to switchcommunications. Accordingly, ISLs may expose the SAN to disruptions fromevents that would be trivial if occurring on a normal device link (e.g.,an N_Port). For example, the routing tables may be changed in allswitches within the fabric when any E_Port connection is altered.

SUMMARY

According to an embodiment described herein, a system can include aprocessor to send a query fabric path command to a switch, the queryfabric path command including an origin address and a destinationaddress. The processor can also receive a query fabric path responsefrom the switch based on the query fabric path command, the query fabricpath response including a plurality of port identifiers. The processorcan also monitor a plurality of ports, each of the plurality of portscorresponding to a respective port identifier of the plurality of portidentifiers in the query fabric path response.

According to another embodiment described herein, a method can includesending a query fabric path command to a switch, the query fabric pathcommand including an origin address and a destination address. Themethod can also include receiving a query fabric path response from theswitch based on the query fabric path command, the query fabric pathresponse including a plurality of port identifiers. The method can alsoinclude monitoring a plurality of ports, each of the plurality of portscorresponding to a respective port identifier of the plurality of portidentifiers in the query fabric path response.

According to another embodiment described herein, a computer programproduct can include a computer readable storage medium having programinstructions embodied therewith, the program instructions executable bya processing device to cause the processing device to perform a methodincluding sending a query fabric path command to a switch, the queryfabric path command including an origin address and a destinationaddress. The method can also include receiving a query fabric pathresponse from the switch based on the query fabric path command, thequery fabric path response including a plurality of port identifiers.The method can also include monitoring a plurality of ports, each of theplurality of ports corresponding to a respective port identifier of theplurality of port identifiers in the query fabric path response.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example computer system for use inconjunction with one or more embodiments of inter-switch link (ISL)identification and monitoring;

FIGS. 2A-C are a block diagrams of systems for ISL identification andmonitoring in accordance with one or more embodiments of the presentinvention; and

FIG. 3 is a process flow diagram of a method for ISL identification andmonitoring in accordance with one or more embodiments of the presentinvention.

DETAILED DESCRIPTION

One or more embodiments of the present invention provide inter-switchlink (ISL) identification and monitoring. Endpoints, including but notlimited to servers or disks, that are connected by a storage areanetwork (SAN) fabric may not be aware of the path (e.g., specific ISLs)taken through the SAN fabric between any two endpoints. Link failures onone or more ISLs of a fabric may cause connectivity failures at theendpoints. Read diagnostic parameters (RDP) requests may be issued by anendpoint to query a switch for information on any port of the SANfabric. However, an endpoint may only have knowledge of the N-Portbetween the endpoint and a switch, and the N-Port between a destinationendpoint and another switch. Any intermediate E-Ports may not be known.Embodiments of ISL identification and monitoring described herein allowan origin endpoint to query a switch for information regarding the paththrough the SAN fabric to a destination endpoint. With this knowledge,the origin endpoint may monitor the ports in the path(s) between theorigin and destination endpoints by periodically requesting RDPinformation from the various ports. The RDP information allows theorigin endpoint to identify any potentially failing ports, so thatproblems in any ISLs between the origin and destination endpoints may beidentified and isolated before failure occurs.

Turning now to FIG. 1, a computer system 100 is generally shown inaccordance with an embodiment. The computer system 100 can be anelectronic, computer framework comprising and/or employing any numberand combination of computing devices and networks utilizing variouscommunication technologies, as described herein. The computer system 100can be easily scalable, extensible, and modular, with the ability tochange to different services or reconfigure some features independentlyof others. The computer system 100 may be, for example, a server,desktop computer, laptop computer, tablet computer, or smartphone. Insome examples, computer system 100 may be a cloud computing node.Computer system 100 may be described in the general context of computersystem executable instructions, such as program modules, being executedby a computer system. Generally, program modules may include routines,programs, objects, components, logic, data structures, and so on thatperform particular tasks or implement particular abstract data types.Computer system 100 may be practiced in distributed cloud computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network. In a distributed cloudcomputing environment, program modules may be located in both local andremote computer system storage media including memory storage devices.

As shown in FIG. 1, the computer system 100 has one or more centralprocessing units, i.e., CPUs 101 a, 101 b, 101 c, etc. (collectively orgenerically referred to as processor 101). The processors 101 can be asingle-core processor, multi-core processor, computing cluster, or anynumber of other configurations. The processors 101, also referred to asprocessing circuits, are coupled via a system bus 102 to a system memory103 and various other components. The system memory 103 can include aread only memory (ROM) 104 and a random access memory (RAM) 105. The ROM104 is coupled to the system bus 102 and may include a basicinput/output system (BIOS), which controls certain basic functions ofthe computer system 100. The RAM is read-write memory coupled to thesystem bus 102 for use by the processors 101. The system memory 103provides temporary memory space for operations of said instructionsduring operation. The system memory 103 can include random access memory(RAM), read only memory, flash memory, or any other suitable memorysystems.

The computer system 100 comprises an input/output (I/O) adapter 106 anda communications adapter 107 coupled to the system bus 102. The I/Oadapter 106 may be a small computer system interface (SCSI) adapter thatcommunicates with a hard disk 108 and/or any other similar component.The I/O adapter 106 and the hard disk 108 are collectively referred toherein as a mass storage 110.

Software 111 for execution on the computer system 100 may be stored inthe mass storage 110. The mass storage 110 is an example of a tangiblestorage medium readable by the processors 101, where the software 111 isstored as instructions for execution by the processors 101 to cause thecomputer system 100 to operate, such as is described herein below withrespect to the various Figures. Examples of computer program product andthe execution of such instruction is discussed herein in more detail.The communications adapter 107 interconnects the system bus 102 with anetwork 112, which may be an outside network, enabling the computersystem 100 to communicate with other such systems. In one embodiment, aportion of the system memory 103 and the mass storage 110 collectivelystore an operating system, which may be any appropriate operatingsystem, such as the z/OS or AIX operating system from IBM Corporation,to coordinate the functions of the various components shown in FIG. 1.

Additional input/output devices are shown as connected to the system bus102 via a display adapter 115 and an interface adapter 116 and. In oneembodiment, the adapters 106, 107, 115, and 116 may be connected to oneor more I/O buses that are connected to the system bus 102 via anintermediate bus bridge (not shown). A display 119 (e.g., a screen or adisplay monitor) is connected to the system bus 102 by a display adapter115, which may include a graphics controller to improve the performanceof graphics intensive applications and a video controller. A keyboard121, a mouse 122, a speaker 123, etc. can be interconnected to thesystem bus 102 via the interface adapter 116, which may include, forexample, a Super I/O chip integrating multiple device adapters into asingle integrated circuit. Suitable I/O buses for connecting peripheraldevices such as hard disk controllers, network adapters, and graphicsadapters typically include common protocols, such as the PeripheralComponent Interconnect (PCI). Thus, as configured in FIG. 1, thecomputer system 100 includes processing capability in the form of theprocessors 101, and, storage capability including the system memory 103and the mass storage 110, input means such as the keyboard 121 and themouse 122, and output capability including the speaker 123 and thedisplay 119.

In some embodiments, the communications adapter 107 can transmit datausing any suitable interface or protocol, such as the internet smallcomputer system interface, among others. The network 112 may be acellular network, a radio network, a wide area network (WAN), a localarea network (LAN), or the Internet, among others. An external computingdevice may connect to the computer system 100 through the network 112.In some examples, an external computing device may be an externalwebserver or a cloud computing node.

It is to be understood that the block diagram of FIG. 1 is not intendedto indicate that the computer system 100 is to include all of thecomponents shown in FIG. 1. Rather, the computer system 100 can includeany appropriate fewer or additional components not illustrated in FIG. 1(e.g., additional memory components, embedded controllers, modules,additional network interfaces, etc.). Further, the embodiments describedherein with respect to computer system 100 may be implemented with anyappropriate logic, wherein the logic, as referred to herein, can includeany suitable hardware (e.g., a processor, an embedded controller, or anapplication specific integrated circuit, among others), software (e.g.,an application, among others), firmware, or any suitable combination ofhardware, software, and firmware, in various embodiments.

FIGS. 2A-C are block diagrams of a system 200A-C that includes ISLidentification and monitoring in accordance with one or more embodimentsof the present invention. System 200A of FIG. 2A includes a server 201that is in communication with a disk 205 via a SAN fabric that includesswitch 202, ISLs 203A-E, and switch 204. Any of server 201, disk 205,and switches 202 and 204 may include any of the elements discussed abovewith respect to computer system 100 of FIG. 1. Server 201 and disk 205are endpoints of the SAN fabric that includes switch 202, switch 204 andISLs 203A-E. Server 201 is directly connected to port 240 (e.g., anN_Port) on switch 202, and disk 205 is directly connected to port 241(e.g., an N_Port) on switch 204. Each of ISLs 203A-E are connected to arespective port (e.g., an E_Port) of ports 230A-E and ports 231A-E oneach of switch 202 and switch 204. ISL 203A is located between ports230A and 231A; ISL 203B is located between ports 230B and 231B; ISL 203Cis located between ports 230C and 231C; ISL 203D is located betweenports 230D and 231D; and ISL 203E is located between ports 230E and231E. ISLs 203A-E may each include any appropriate number ofintermediate switches (including additional ports) and links in variousembodiments. The multiple ISLs 203A-E may provide capacity andredundancy for the connection between switches 202 and 204.

Various embodiments of system 200A may implement a static routing modeor a dynamic routing mode between server 201 and disk 205. In the staticrouting mode, the switches 202 and 204 may use a defined ISL for eachdirection of traffic between two endpoints. For example, for outboundtraffic from server 201 to disk 205, the switch 202 may use ISL 203B,and for inbound traffic from disk 205 to server 201, switch 204 may useISL 203D. In the dynamic routing mode, any of the ISLs 203A-E may beused for traffic in any direction between the server 201 and disk 205.Any switches, such as switches 202 and 204 in the SAN fabric of system200A, may include a routing table that specifies the routing modes andISLs for the various connections between endpoints of the SAN fabric; aSAN fabric may include any appropriate number of endpoints.

Failures may occur in any of ISLs 203A-E. For example, in the staticrouting mode described above between server 201 and disk 205, ISL 203Bmay exhibit problems before a failure occurs in the ISL 203B.Identification of a potential future failure may allow remedial measuresto be taken before the failure occurs (e.g., in static routing mode,selecting a different ISL, e.g., ISL 203C, for outbound traffic betweenserver 201 and disk 205, and updating the routing tables based on theselected ISL). A failure in ISL 203B may impact frames sent from theserver 201 to the disk 205, as well frames sent between any otherendpoints that use ISL 203B. In dynamic routing mode, a failure in asingle ISL such as ISL 203B may impact traffic on other ISLs such as ISL203A, 203C, and 203D.

System 200B of FIG. 2B shows an exchange of messages that are passedbetween the server 201 and the switch 202 in system 200A in accordancewith one or more embodiments of ISL identification and monitoring. Theserver 201 sends a query fabric path command 206 to the switch 202 torequest information regarding the specific ISLs (e.g., of ISLs 203A-E)that are used to transport data (e.g., frames or packets) of a sourceport and destination port pair between the server 201 and the disk 205.The switch 202 responds to the query fabric path command 206 with aquery fabric path response 207. The query fabric path response 207 maylist ports that are included in the ISLs that are used in the connectionbetween the server 201 and the disk 205. The server 201 may then monitorthe ports that were listed in the query fabric path response 207 byperiodically sending a plurality of RDP requests, such as RDP request208, to any ports that were listed in the query fabric path response207. The ports each return an RDP response such as RDP response 209 tothe server 201 in response to the RDP requests such as RDP request 208.An RDP response 209 may include any appropriate data regarding the portthat sent the RDP response 209, such as voltage, current, andtemperature information. The RDP requests may be sent by the server 201periodically, and the health of the various ports may be monitored basedon the resulting RDP responses during operation of the SAN fabric ofsystem 200A.

If it is determined that a port is exhibiting signs of failure based onthe RDP responses 209 that were sent by the port to the monitoringendpoint, an ISL (e.g., ISL 203B) associated with the failing port maybe preemptively taken offline before the failure occurs. In someembodiments, a monitoring endpoint (e.g., server 201) may issue controlunit port (CUP) commands to decommission an ISL associated with afailing port, and may also notify the SAN administrator of the failingport. While in system 200B of FIG. 2B, the server 201 is shown assending the query fabric path command 206 to switch 202, in someembodiments, any endpoint in a SAN fabric (e.g., server 201 or disk 205)may send a query fabric path command 206 to a directly connected switch(e.g., switch 202 or 204), and may periodically send RDP requests 208 toany ports listed in a received query fabric path response 207.

System 200C of FIG. 2C shows a query fabric path command 206 and a queryfabric path response 207 in accordance with one or more embodiments ofISL identification and monitoring. The query fabric path command 206includes an origin endpoint address 210 (e.g., in an embodiment in whichthe server 201 is sending the query fabric path command 206, theidentifier of a connection to server 201), a destination endpointaddress 211 (e.g., in an embodiment in which the server 201 is sendingthe query fabric path command 206, the identifier of a connection todisk 205), and a path number 212. The path number 212 may correspond tothe ISL(s) that make up the Nth shortest path between the originendpoint and destination endpoint that the origin endpoint wishes tomonitor. The Nth shortest path may be determined by any appropriatealgorithm, such as a fabric shortest path first (FSPF) routing protocol.N may be any appropriate number in various embodiments, and may beconfigured by an administrator of the origin endpoint in someembodiments. A query fabric path command such as query fabric pathcommand 206 may be sent to a switch, such as switch 202 or switch 204,by any endpoint (e.g., server 201 or disk 205) in a SAN fabric such asis illustrated by system 200A; the sending endpoint of the query fabricpath command 206 is the origin endpoint.

The query fabric path response 207 includes a list of outbound pathports 220, a list of inbound path ports 221, and a routing mode 222. Thelist of outbound path ports 220 includes port identifiers for any switchports (e.g., E_Ports) included in the outbound data path from the originendpoint (e.g., server 201) to the destination endpoint (e.g., disk205). The list of inbound ports includes port identifiers for any switchports (e.g., E_Ports) included in the inbound data path from thedestination endpoint (e.g., disk 205) to the origin endpoint (e.g.,server 201). The routing mode 222 indicates whether the routing betweenthe origin endpoint and the destination endpoint is static or dynamic.If the routing mode 222 is static, the ports listed in outbound pathports 220 and inbound path ports 221 correspond to the static paths thatare used (e.g., ISL 203B for outbound path ports, and ISL 203D forinbound path ports). If the routing mode 222 is dynamic, the portslisted in outbound path ports 220 and inbound path ports 221 correspondto the members of the Nth shortest path (which may be determined by FSPFor any other appropriate algorithm) between the origin endpoint anddestination endpoint, as specified by the path number 212 in queryfabric path command 206. A query fabric path response such as queryfabric path response 207 may be sent from a switch, such as switch 202or switch 204, to any endpoint (e.g., server 201 or disk 205) in a SANfabric such as is illustrated by system 200A in response to a queryfabric path command 206. In some embodiments, the query fabric pathresponse 207 may also include an indication of whether there is any linkaggregation in use between the origin and destination endpoints, and ifthere is link aggregation, which link is the master and which link(s)are members (e.g., of ISLs 203A-E).

Any endpoint (e.g., a server or a disk) in a SAN fabric, such as isshown in system 200A of FIG. 2A, may send a query fabric path command206 to a directly connected switch. In some embodiments of a system 200Aincluding a SAN fabric, each endpoint in the SAN fabric may monitor thepath between itself and all other endpoints that communicate with theendpoint. In such embodiments, each endpoint may send a query fabricpath command 206 for each other endpoint that is in communication withthe endpoint. Each endpoint may then periodically send RDP requests 208to all ports listed in any query fabric path responses 207 that arereceived by the endpoint. The ports may be monitored for signs offailure by the origin endpoint based on RDP responses 209 that arereceived in response to the RDP requests 208. In some embodiments of asystem 200A including a SAN fabric, a single endpoint that is incommunication with a plurality of other endpoints may be designated toperform port monitoring for each of the plurality of connections betweenthe single endpoint and the plurality of other endpoints (e.g., a serverthat is in communication with a plurality of disks may monitor the portsthat are included in the paths between itself and each of the pluralityof disks). Any endpoint in a SAN fabric may perform port monitoring,including sending RDP requests and receiving RDP responses, based onquery fabric path commands and responses.

In an example SAN fabric corresponding to systems 200A-C of FIGS. 2A-Cthat implements link aggregation, the routing tables in the switches 202and 204 may specify that, for traffic from server 201 to disk 205, agroup including ISLs 203A and 203B are used, with ISL 203A being amaster link, and, for traffic from disk 205 to server 201, a groupincluding ISLs 203C, 203D, and 203E are used, with ISL 203C being amaster link. For a query fabric path command 206 sent by server 201 toswitch 202 regarding the path(s) to and from disk 205, the path number212 may be 1. In the query fabric path response 207, the list ofoutbound path ports 220 may include port identifiers for ports 230A and231A as master, and also ports 230B and 231B. The list of inbound pathports 221 may include port identifiers for ports 230C and 231C asmaster, and also ports 230D, 231D, 230E, and 231E. The routing mode 222may be static. The server 201 may send periodic RDP requests 208 toports 230A-E and 231A-E based on the query fabric path response 207 inorder to monitor for any failures in ISLs 203A-E.

It is to be understood that the block diagrams of FIG. 2A-C are notintended to indicate that the systems 200A-C are to include all of thecomponents shown in FIGS. 2A-C. Rather, the systems 200A-C can includeany appropriate fewer or additional components not illustrated in FIG.2A-C (e.g., additional servers, disks, switches, ISLs, commands,requests, responses, command fields, request fields, response fields,etc.). Further, the various servers and disks may be interconnected inany appropriate manner by any appropriate number of switches and ISLs.Further, the embodiments described herein with respect to systems 200A-Cmay be implemented with any appropriate logic, wherein the logic, asreferred to herein, can include any suitable hardware (e.g., aprocessor, an embedded controller, or an application specific integratedcircuit, among others), software (e.g., an application, among others),firmware, or any suitable combination of hardware, software, andfirmware, in various embodiments.

FIG. 3 is a process flow diagram of a method 300 for ISL identificationand monitoring in accordance with one or more embodiments of the presentinvention. Some embodiments of method 300 of FIG. 3 may be implementedin systems 200A-C that are shown in FIGS. 2A-C. In block 301, an originendpoint (such as server 201 and/or disk 205) of FIGS. 2A-B, in a SANfabric sends a query fabric path command 206 to a switch (such as switch202 and/or switch 204) for a particular destination endpoint (such asdisk 205 and/or server 201). The query fabric path command 206 includesan origin endpoint address 210, a destination endpoint address 211, anda path number 212 (e.g., Nth shortest path) that the origin endpointwishes to monitor. The path number 212 may be any appropriate number,and may be set by an administrator of the origin endpoint in someembodiments.

In block 302, the switch sends a query fabric path response 207 to theorigin endpoint in response to the query fabric path command 206 ofblock 301. The query fabric path response 207 includes a list ofoutbound path ports 220, a list of inbound path ports 221, and a routingmode 222. The routing mode 222 may be either static or dynamic in someembodiments. The port identifiers included in the list of outbound pathports 220 and list of inbound path ports 221 may be determined based onthe path number 212. For example, for a dynamic routing mode connectionbetween the origin endpoint and destination endpoint, there may be aplurality of ISLs in use. In an embodiment in which the path number 212is two, only port identifiers for ports that are included in the secondshortest path (as determined by FSPF or any other appropriate algorithm)between the origin endpoint and the destination endpoint may be includedin the list of outbound path ports 220 and list of inbound path ports221 in query fabric path response 207. In some embodiments, the queryfabric path response 207 that is sent in block 302 may include anindication of whether there is any link aggregation in use between theorigin and destination endpoints, and if there is link aggregation,which ISL is the master and which ISL(s) are members.

In block 303, the origin endpoint sends periodic RDP requests 208 toeach of the ports listed in both the list of outbound path ports 220 andthe list of inbound path ports 221 in the query fabric path response207. RDP responses 209 are received in block 303 in response to each ofthe RDP requests 208. An RDP response 209 may include any appropriateinformation regarding the sending port, including but not limited tovoltage, current, and temperature information. In block 304, based onthe RDP responses 209 that are received in response to the periodic RDPrequests 208, the origin endpoint may identify a failing port, and mayperform remedial action, such as taking an ISL (e.g., any of ISLs203A-E) that is associated with the failing port offline before failureoccurs. The origin endpoint may notify the switch that includes thefailing port that was identified in block 304. In some embodiments, theorigin endpoint may issue control unit protocol (CUP) commands todecommission an ISL associated with a failing port, and may also notifythe SAN administrator of the failing port in block 304. Routing tablesin the switches of the SAN fabric may be updated based on the remedialaction of block 304.

The process flow diagram of FIG. 3 is not intended to indicate that theoperations of the method 300 are to be executed in any particular order,or that all of the operations of the method 300 are to be included inevery case. Additionally, the method 300 can include any suitable numberof additional operations.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, configuration data for integrated circuitry, oreither source code or object code written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Smalltalk, C++, or the like, and procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The computer readable program instructions may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider). In some embodiments, electronic circuitry including,for example, programmable logic circuitry, field-programmable gatearrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instruction by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdescribed herein.

1. A system comprising a processor and a memory configured to: send aquery fabric path command from an origin endpoint to a first switch, thequery fabric path command including an origin address corresponding tothe origin endpoint and a destination address corresponding to adestination endpoint; receive a query fabric path response from thefirst switch based on the query fabric path command, the query fabricpath response including a plurality of port identifiers, wherein theplurality of port identifiers correspond to a plurality of expansionports (E_Ports) of a plurality of inter-switch links (ISLs) between thefirst switch and a second switch, and wherein each of the plurality ofISLs is configured to transmit traffic between the origin endpoint andthe destination endpoint; and monitor the plurality of E_Ports.
 2. Thesystem of claim 1, wherein the query fabric path response includes arouting mode for a connection between the origin address and thedestination address, the routing mode comprising one of static routingand dynamic routing.
 3. The system of claim 1, wherein the plurality ofport identifiers comprises a plurality of outbound path ports used fortraffic from the origin address to the destination address, and aplurality of inbound path ports used for traffic from the destinationaddress to the origin address.
 4. The system of claim 3, wherein theplurality of outbound path ports includes a designation of an outboundmaster link, and the plurality of inbound path ports includes adesignation of an inbound master link.
 5. The system of claim 1, whereinthe query fabric path command includes a path number, and wherein theplurality of port identifiers in the query fabric path responsecorrespond to the path number based on a fabric shortest path first(FSPF) protocol.
 6. The system of claim 1, wherein the monitoring of theplurality of E_Ports comprises: sending a respective read diagnosticparameters (RDP) request from the origin address to each of theplurality of E_Ports; receiving an RDP response from each E_port of theplurality of E_Ports at the origin address, wherein each RDP responseincludes at least one of voltage data, current data, and temperaturedata corresponding to the port that sent the RDP response; andidentifying a failing port of the plurality of E_Ports based on at leastone of the voltage data, current data, and temperature data included inan RDP response from the failing port.
 7. The system of claim 6, whereinthe processor is further configured to: preemptively take an ISLassociated with the failing port offline based on identifying thefailing port before a failure occurs in the failing port.
 8. Acomputer-implemented method, comprising: sending, by a processor, aquery fabric path command from an origin endpoint to a first switch, thequery fabric path command including an origin address corresponding tothe origin endpoint and a destination address corresponding to adestination endpoint; receiving, by the processor, a query fabric pathresponse from the first switch based on the query fabric path command,the query fabric path response including a plurality of portidentifiers, wherein the plurality of port identifiers correspond to aplurality of expansion ports (E_Ports) of a plurality of inter-switchlinks (ISLs) between the first switch and a second switch, and whereineach of the plurality of ISLs is configured to transmit traffic betweenthe origin endpoint and the destination endpoint; and monitoring, by theprocessor, the plurality of E_Ports.
 9. The computer-implemented methodof claim 8, wherein the query fabric path response includes a routingmode for a connection between the origin address and the destinationaddress, the routing mode comprising one of static routing and dynamicrouting.
 10. The computer-implemented method of claim 8, wherein theplurality of port identifiers comprises a plurality of outbound pathports used for traffic from the origin address to the destinationaddress, and a plurality of inbound path ports used for traffic from thedestination address to the origin address.
 11. The computer-implementedmethod of claim 10, wherein the plurality of outbound path portsincludes a designation of an outbound master link, and the plurality ofinbound path ports includes a designation of an inbound master link. 12.The computer-implemented method of claim 8, wherein the query fabricpath command includes a path number, and wherein the plurality of portidentifiers in the query fabric path response correspond to the pathnumber based on a fabric shortest path first (FSPF) protocol.
 13. Thecomputer-implemented method of claim 8, wherein the monitoring of theplurality of ports comprises: sending a respective read diagnosticparameters (RDP) request from the origin address to each of theplurality of ports; receiving an RDP response from each port of theplurality of ports at the origin address, wherein each RDP responseincludes at least one of voltage data, current data, and temperaturedata corresponding to the port that sent the RDP response; andidentifying a failing port of the plurality of ports based on at leastone of the voltage data, current data, and temperature data included inan RDP response from the failing port.
 14. The computer-implementedmethod of claim 13, the method comprising: preemptively taking an ISLassociated with the failing port offline based on identifying thefailing port before a failure occurs in the failing port.
 15. A computerprogram product comprising: a computer readable storage medium havingprogram instructions embodied therewith, the program instructionsexecutable by a processing device to cause the processing device toperform a method comprising: sending a query fabric path command from anorigin endpoint to a first switch, the query fabric path commandincluding an origin address corresponding to the origin endpoint and adestination address corresponding to a destination endpoint; receiving aquery fabric path response from the first switch based on the queryfabric path command, the query fabric path response including aplurality of port identifiers, wherein the plurality of port identifierscorrespond to a plurality of expansion ports (E_Ports) of a plurality ofinter-switch links (ISLs) between the first switch and a second switch,and wherein each of the plurality of ISLs is configured to transmittraffic between the origin endpoint and the destination endpoint; andmonitoring the plurality of E_Ports.
 16. The computer program product ofclaim 15, wherein the query fabric path response includes a routing modefor a connection between the origin address and the destination address,the routing mode comprising one of static routing and dynamic routing.17. The computer program product of claim 15, wherein the plurality ofport identifiers comprises a plurality of outbound path ports used fortraffic from the origin address to the destination address, and aplurality of inbound path ports used for traffic from the destinationaddress to the origin address.
 18. The computer program product of claim17, wherein the plurality of outbound path ports includes a designationof an outbound master link, and the plurality of inbound path portsincludes a designation of an inbound master link.
 19. The computerprogram product of claim 15, wherein the query fabric path commandincludes a path number, and wherein the plurality of port identifiers inthe query fabric path response correspond to the path number based on afabric shortest path first (FSPF) protocol.
 20. The computer programproduct of claim 15, wherein the monitoring of the plurality of portscomprises: sending a respective read diagnostic parameters (RDP) requestfrom the origin address to each of the plurality of ports; receiving anRDP response from each port of the plurality of ports at the originaddress, wherein each RDP response includes at least one of voltagedata, current data, and temperature data corresponding to the port thatsent the RDP response; and identifying a failing port of the pluralityof ports based on at least one of the voltage data, current data, andtemperature data included in an RDP response from the failing port.